The present invention relates to a control apparatus for an internal combustion engine.
A variable valve control mechanism capable of varying valve lift characteristics of an intake valve continuously is disclosed in Unexamined Japanese Patent Publication No. 2002-89341 which is assigned to the same assignee of this application. The variable valve control mechanism includes in combination an operation angle varying mechanism capable of varying an operation angle of an intake valve continuously and a phase varying mechanism capable of varying a maximum lift phase of an intake valve (i.e., the phase at which the lift of the intake valve becomes maximum).
Further, Unexamined Japanese Patent Publication No. 9-203337 discloses a technique for obviating a difference in air/fuel ratio between cylinders by detecting an air/fuel ratio of each cylinder through comparison between a time variation of a detection signal of an air/fuel ratio sensor and an exhaust timing of each cylinder and feedback correcting a fuel injection quantity independently of each cylinder.